Consistent alignment mark profiles on semiconductor wafers using metal organic chemical vapor deposition titanium nitride protective
AssigneeLSI Corporation
InventorsJoe W. Zhao, Shumay X. Dou, Keith K. Chao
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Abstract
Provided is a method and composition for protecting alignment mark trench walls from attack by CMP slurry accumulating in an alignment mark trench during CMP processing. In a preferred embodiment, a metal organic chemical vapor deposition titanium nitride (MOCVDTiN) layer is deposited over a conventionally applied bulk tungsten layer prior to commencing CMP operations. This MOCVDTiN layer is resistant to CMP slurry attack. As a result, the tungsten trench profile remains a consistent and reliable alignment mark.
Claims12
A method of forming an alignment mark on a semiconductor wafer, comprising:
- providing a semiconductor wafer having a trench in a surface layer;
- depositing a layer of metal in said trench;
- depositing a protective layer of metal organic chemical vapor deposition titanium nitride over said metal layer;
- and
- planarizing said wafer surface by chemical mechanical polishing;
- wherein said protective layer reduces the rate and increases the uniformity of attack of side walls of the alignment mark trench by chemical mechanical polishing slurry accumulating in the trench during the planarization step.
A method for forming an alignment mark on a semiconductor wafer, comprising:
- providing a semiconductor wafer having a trench in a surface dielectric layer;
- depositing a base layer of equiaxed grain tungsten in said trench;
- depositing a bulk layer of columnar tungsten over said base layer;
- depositing a protective layer of metal organic chemical vapor deposition titanium nitride over said bulk layer;
- and
- planarizing said wafer surface by chemical mechanical polishing;
- wherein said protective layer reduces the rate and increases the uniformity of attack of side walls of the alignment mark trench by chemical mechanical polishing slurry accumulating in the trench during the planarization step.
Dependencies are inferred from the claim text.